**Author details**

94 Recent Advances in Crystallography

by co-crystallization.

entire process.

successful outcome.

**6. Conclusions** 

the chip or adjustments to that system. These capabilities of the X-CHIP make it a potentially useful platform for high-throughput initiatives such as fragment-based screening

The X-CHIP system has the potential to completely remove the "user factor" between crystal growth and X-ray diffraction data collection, eliminating crystal manipulation. The feasibility of *in situ* data collection has significant implications. Firstly, data collection at room temperature eliminates the need for the tedious and often limiting step of cryocondition optimization with the added advantage that crystal structures determined at room temperature are more representative of the physiological state. Additionally, experimentally obtained SAD data displayed excellent processing statistics, clearly of sufficient quality for *de novo* structure determination. Interestingly, in at least one of the cases investigated, undisturbed crystals have shown significantly lower mosaic spread than that of cryogenically frozen samples, suggesting the potential application of this system to samples of high sensitive or ones with a large unit cell (Table 1). Once mounted on the goniometer, navigation along the chip and alignment of any crystal in the drops is quite straightforward, presenting the potential for data collection in a high-throughput mode. This approach eliminates the necessity for mounting of individual loops as in conventional robotics systems and may save hours of valuable synchrotron beam time. Finally, the elimination of manual crystal handling opens the opportunity for full automation of the crystallization to data acquisition pipeline allowing streamlining of the

Current developments on the project are aimed at scaling down the drop volumes of the X-CHIP system. Attempting to do so using manual set up has proven to be challenging, but application of a liquid handling robotics system can address this issue. The *Mosquito*  crystallization robotic system (Molecular Dimensions Ltd., Suffolk, UK) has already been used to successfully set up crystallization experiments with total drop volumes as low as 200nl. The X-CHIP is also being applied to the crystallization trials of additional protein targets. As a point of interest, experiments with highly sensitive and/or small crystal samples could greatly benefit from the use of this system, as the non-invasive data collection approach would likely resolve many problems that arise from crystal handling. We are also exploring the application of the chip for projects in which low mosaic spread is essential for

From the initial studies of the device it is evident that not only does the X-CHIP have the potential to increase efficiency and offer on-the-chip *in situ* data collection for *de nevo* structure determination, but it also has a range of additional benefits including the opportunity for full automation. Even though the recent growth of microchip crystallization technology has seen the development of several useful devices, the X-CHIP platform offers previously unprecedented simplicity with comparable or in some cases even better performance. As seen in the recent growth of commercially available and published Nickolay Y. Chirgadze\*

*Canada Campbell Family Cancer Research Institute, Ontario Cancer Institute, Princess Margaret Hospital, University Health Network, Toronto, Ontario, Canada Department of Pharmacology and Toxicology, University of Toronto, Toronto, Ontario, Canada* 

Gera Kisselman, Wei Qiu, Vladimir Romanov, Christine M. Thompson and Robert Lam *Canada Campbell Family Cancer Research Institute, Ontario Cancer Institute, Princess Margaret Hospital, University Health Network, Toronto, Ontario, Canada* 

Kevin P. Battaile *Hauptman-Woodward Medical Research Institute, IMCA-CAT, Advanced Photon Source, Argonne National Laboratory, Argonne, Illinois, USA* 

Emil F. Pai *Canada Campbell Family Cancer Research Institute, Ontario Cancer Institute, Princess Margaret Hospital, University Health Network, Toronto, Ontario, Canada Departments of Biochemistry, Molecular Genetics, and Medical Biophysics, University of Toronto, Toronto, Ontario, Canada* 
